Last Samples Of Smallpox Pose a Quandary

By HAROLD M. SCHMECK

Published: November 3, 1987

TEN years after smallpox ceased to exist as a human disease, virus experts and public health officials are in a strange and unprecedented quandary: what to do with the last surviving smallpox viruses.

These viruses, the most fearsome endangered species on earth, exist today in only two places, high security laboratories in Moscow and at the Centers for Disease Control in Atlanta.

Now, on the 10th anniversary of the eradication of smallpox, the experts are questioning whether or not those last stocks of variola virus - the cause of smallpox - should finally be destroyed.

''No scientist is working with viable variola virus or is likely to be allowed to do so,'' said Dr. Keith Dumbell, of University of Cape Town, in South Africa, writing in The Lancet, a medical journal.

''To the best of our knowledge,'' he added, ''destruction of all remaining laboratory stocks of variola virus would set the final seal on the attempt to rid the world of this infectious scourge.''

But some specialists have argued that the virus should not be erased altogether from the world, partly because unforeseen research uses might arise in the future and partly simply because once it was destroyed, it could never be raised from extinction. Philosophically, the deliberate extinction of a species would be an unprecedented step.

But this is a species that, over thousands of years, has killed many millions of people and has spread panic and destruction in its wake, often killing one in five of those infected in any outbreak and disfiguring many of the survivors.

Now the only surviving representatives of the virus are stored in little vials kept in freezer lockers at minus 94 degrees Fahrenheit, waiting only for some hypothetical future use.

The high security laboratory in Moscow is now used mainly for diagnostic work on the AIDS virus, according to a doctor who visited there recently. The laboratory at the Centers for Disease Control is also used for other purposes.

The last naturally transmitted case of smallpox occurred in Merka, Somalia, in late October 1977. It is from this case that the 10-year anniversary is dated. The next year, two cases occurred in England because the virus accidentally escaped from a research laboratory. There have been many rumors but no actual cases of smallpox anywhere since then.

Until 1981, research was still done with the live smallpox virus, particularly for the purpose of comparing it with suspects brought in from rumored smallpox cases anywhere in the world. But even that use of the laboratory stocks is no longer necessary because advances in molecular biology have provided a safe alternative. Concern Over Biological Warfare

Most of the genetic material from the virus is now maintained in a collection of circular pieces of DNA called plasmids that can be grown in bacteria. Each plasmid holds a different small portion of the virus DNA, but the total complement of genetic material is not believed to be available anywhere. Specialists say it would not be possible to grow a live virus from even the combined material of the whole plasmid collection.

Dr. Dumbell questioned his fellow virologists throughout the world about the desirability of destroying the virus. Of the 61 scientists in 22 countries who responded, only five thought the virus stocks should be preserved indefinitely.

Those five offered two fundamental reasons: first, that the virus could be kept in storage with minimal risk and that this should be continued to preserve specimens of the species; and second, that the preservation of openly retained stocks was preferable to destroying them and leaving the possibility that some country was keeping secret stocks for possible use in biological warfare.

Such rumors of clandestine virus supplies are fueled by the fact that some countries, notably the United States and the Soviet Union, continue to vaccinate military personnel even though there is no present risk of the disease smallpox anywhere.

Dr. Donald A. Henderson, who was head of the World Health Organization's global smallpox eradication program from 1966 until its successful conclusion, said he doubted that any of the virus exists apart from the known specimens in Moscow and Atlanta, but that the possibility cannot be ruled out that some may exist in the frozen stores of a virologist who has long since forgotten its existence. He considers this highly unlikely and not a major hazard in any case.

As to the biological warfare issue, the smallpox virus is not really considered an ''ideal'' weapon. There are other viruses and other biological agents that would be more effective. Suggestion to White House

Dr. Henderson, who is now dean of Johns Hopkins University's School of Hygiene and Public Health, said yesterday he could see both sides of the quandary. He does not consider the safety of maintaining stocks a major issue.

''As a scientist I would say let's keep it,'' he said, ''but looking at the reality of concerns, I think we would be politically well advised to destroy it.''

In fact, he suggested, an agreement to destroy the last smallpox viruses and also to stop vaccinating troops would be a constructive item for a summit meeting between the two superpowers. He said public health experts had made that suggestion recently to the White House, but there has been no indication that it has been accepted.

In his commentary in The Lancet, Dr. Dumbell made a similar point.

''A mutual agreement for the total abandonment of military vaccinations and the destruction of remaining stocks of variola virus is surely achievable,'' he said. ''Here the W.H.O. could be the best mediator. The smallpox eradication campaign was built on a foundation of international cooperation. It would be fitting if the last act of the drama were to be in the same vein of international accord.''